This invention relates to a tunnel shield structure used in the shield method.
In the shield method is used an erector to sequentially assemble segments such as those of reinforced concrete as a shielding machine is propelled. For interconnecting and assembling the respective segments have been developed and proposed various methods and structures while structures generally put to practical use have embedded fittings interconnected through bolts.
Now, when the segments are assembled annularly, they are required to have united yield strength to resist earth pressure while being interconnected integrally in the direction of a tunnel when uneven subsidence may occur in soft ground. Further they may be required to introduce compressive force in the direction of the tunnel to deflect in the longitudinal direction of the tunnel for preventing the subsidence.